1. Field of the Invention
The present invention relates to an electronic warning system for commercial trailer vans and, more particularly, to a plurality of electronically controlled hazardous material signs which can selectively display any one of a number of warnings or symbols on a placard, required by the U.S. Department of Transportation to be posted on the exterior of a commercial trailer van while hauling hazardous substances.
2. Description of Relevant Art
When a commercial trailer is used to haul a hazardous material, a sign indicating the hazardous material is required to be placed on all four sides of the trailer. The particular signs used for identifying hazardous materials are mandated by the U.S. Department of Transportation. These signs are in the form of a diamond shaped sign which identifies the substance and the nature of the hazard (i.e., radiation, fire or explosive, etc.) Whenever the contents of the trailer are changed, however, a driver must change the hazardous materials signs present on the trailer. To avoid the need for repeated changing of the hazardous materials signs, it is desirable to provide electronically controlled signs which can display any of the required hazardous materials signs, or any other similar warning signs.
The relevant art describes various means of including warning and advertising signs on particular vehicles, and will be discussed in the order of perceived relevance to the present invention.
U.S. Pat. No. 4,574,269 issued on Mar. 4, 1986, to Gregory R. Miller describes a visual communicator for a rear window of a vehicle. The message display unit is semi-transparent and includes a matrix of light emitting diodes energized by a message control unit. Selected words such as "PASS" and "THANKS" are shown on the message display unit. There is no suggestion to apply this unit to display signs with various colors and designs.
U.S. Pat. No. 4,094,083 issued on Jun. 13, 1978, to Harry Fund describes a vehicle placarding apparatus consisting of imprinted plates hinged to a diamond-shaped base and frame to show a single inscription for hazardous cargo, especially for roll-up rear doors of trailers. The first configuration has only two rectangular plates suitable only for a solid wall. The second configuration has four triangular plates, and is designed only for a roll-up door to fit over two adjacent door segments. These signs are fastened to the walls of the trailer and to the roll-up rear door. There is no suggestion for substituting an integral illuminated diamond for signifying hazardous cargo.
U.S. Pat. No. 4,974,354 issued on Dec. 4, 1990, to Norbert Hembrook, Jr., describes a visual display device for vehicles. A rectangular frame has multiple (five or more) translucent or transparent panels with each panel having cone shaped notches (uncolored) to form letters of a message such as "HELP". The specific printed panel is illuminated from staggered light emitting diodes (LED) or incandescent light bulbs positioned in supports at the top and bottom edges of the rectangular sign. The conductor wires in the horizontal supports can optionally be replaced by a printed circuit board. The specific sign is selected and energized, respectively, by an electrical message control unit located in the cab and the vehicle battery. There is no suggestion for utilizing the LED's or incandescent light bulbs in a single plane for the cone-shaped notches. The present invention utilizes only one panel incorporating the versatility of posting multiple signs.
U.S. Pat. No. 5,450,058 issued on Sep. 12, 1995, to Stanton E. Collier describes a highway deployable directional hazard sign dispensable from the rear of a police vehicle to warn oncoming vehicles of a stopped vehicle. The impact warning device has an elevated light bar consisting of at least six lighting panels which are programmed to either point sequentially to the left or right with arrowheads at the end panels. A battery is provided in the device for energizing the lights and to sound a horn if the sign is impacted. There is no suggestion for either substituting lettered signs or for posting on the sides of a trailer.
European Patent Application No. 0 537 882 A1 published on Apr. 21, 1993, for Courtney B. Bailey describes a mobile or stationary advertising sign having up to five large screens housed in a vehicle and having its own electricity generator and air conditioning system. Video projectors and speaker systems are provided for each translucent screen to create the advertisement. There is no suggestion for providing lettered signs by the use of LED's or the like.
U.S. Pat. No. 4,446,643 issued on May 8, 1984, to Shozo Fujita et al. describes a movable display sign housed in a trailer. The signs are created on lateral surfaces of the trailer by either monochromatic cathode ray tubes or colored light emitting tubes which create a heat build-up within the trailer. The solution is to include a plurality of air conditioners inside the trailer. There is no suggestion for substituting other illuminated devices.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus, an electronic warning system solving the aforementioned problems is desired.